The present invention relates to a sensor device for a vehicle seat, with the sensor being for detecting forces inside the vehicle seat.
A known sensor device of this type serves to determine the seat load by measuring the total weight of the vehicle seat. This data, for example, can trigger the inflation of the airbag. Problems may occur in distinguishing between light adults and heavy children in child seats. The sensor device is installed, for example, as a large-surface component between the seat underframe and the floor group.
One aspect of the present invention is the provision of improvements to a sensor device for a vehicle seat. In accordance with this aspect, a bearing area is positioned between two components of the vehicle seat so that there can be relative movement between the two components, and a sensor device, which includes at least one sensor, is installed in the bearing area for detecting forces inside the vehicle seat.
By installing the sensor device in the bearing area, i.e. in the direct force flow between the part of the vehicle seat above the bearing area and the part of the vehicle seat and the vehicle frame below the bearing area, it is possible to measure bearing forces occurring at this point which will allow conclusions to be drawn with respect to the seat load at this point. Electrical signals of the sensor or sensors can be evaluated and used for compensating measures or the activation of safety components such as airbags. The arrangement, preferably as a socket between the two components which are moveable relative to one another, can be easily mounted directly in the bearing area; because of its small dimensions it does not take up much space. It can be integrated into existing bearing areas, e.g. in articulated height adjusters, by slightly modifying the bearing areas. No additional adapters are required, for example, between the height adjuster and the connection with the vehicle floor group. Through the installation in at least three, and preferably four, bearing areas located approximately on an horizontal level, the position of the occupant can be determined.
The bearing forces, i.e. their size and direction or components, can be precisely determined with a minimum of three sensors in the direction of the circumference. By distinguishing the direction of the forces, it will be possible to distinguish between exclusive weight forces and horizontal force components. Reaction forces which might be produced by the lever mechanisms of a height adjuster and/or inclination adjuster are filtered out. For this purpose, the sensors are installed preferably inside the socket or in the gaps between different bearing elements of the socket which are installed one inside the other. It will be possible to determine pivoting moments by means of additional sensors in the axial direction of the socket.
Preferably, the outer contour of the socket has a single deviation, i.e. an asymmetry, from an otherwise regular form, e.g. a tongue or indentation. In this case, the receiving part of the bearing area preferably has a corresponding asymmetry so that when the socket is mounted it may be given a defined alignment for calibration.